Movable platform resting on an air cushion enclosed inside at least one yielding prefrably circular skirt



Sept. 13, 1966 FAURE 3,272,275

MOVABLE PLATFORM RESTING ON AN AIR CUSHION ENCLOSED INSIDE AT LEAST ONE YIELDING PREFERABLY CIRCULAR SKIRT Filed April 27, 1964 Fig 4 I7 ve 777'? r )4???) are. if

United States Patent France Filed Apr. 27, I964, Ser. No. 362,608

Claims priority, application France, Apr. 29, 1963, 933,105 9 Claims. (Cl. 180-7) The present invention has for its object a movable platform resting on an air cushion enclosed inside at least one yielding, preferably circular skirt.

Applicant has described in the prior specification, Ser. No. 165,634, a deformable skirt for such purposes, which skirt when seen from above shows a circular shape so as to assume a natural stability under the action of the overpressure of the gases contained therein. It is therefore possible to execute said skirt as a very light structure with a particularly yielding material adapted to recede when passing over a hindrance or obstacle on its path.

The present invention improves the yieldingness of such deformable skirts and chiefly of circular skirts having a circular outline in plan view so as to reduce the difliculty arising through the concavity of the rear section of said skirt, which concavity makes the passage of said rear section over a hindrance more difficult than the engagement over the latter of the front section of the skirt.

The invention consists chiefly in providing a sloping gas-permeable partition connected inwardly at least with the lower rear section of the skirt while forming with the ground an acute angle which may be very small. Such an advantageously deformable partition which is secured to the platform is tensioned when the platform passes over a hindrance and raises the rear section of the skirt.

According to a preferred embodiment of the invention which is applicable to deformable skirts having a 0 11- cular shape in plan view and which are of particular interest by reason of their natural stability and uniform omnidirectional properties, the inner gas-permeable partition forms a cone of which the apical angle may reach a value as high as 180". Said cone is made of a meshed material for instance of gauze which is secured through its apex to the platform, if required through the agency of a cable and/or a spring, while it is furthermore secured to the periphery of the skirt just above the lower edge of the latter which may be reinforced in order to resist abrasion under better conditions.

Thus, comparatively sharp hindrances such as stakes and rocks having sharp ridges may readily release the yielding skirt, chiefly when the latter is circular in plan view, while the passage of the skirt over conventional hindrances of a rounded shape such as stones and tree trunks for instance is also furthered.

The following description of an embodiment of the invention illustrated in the accompanying drawings is given by way of example and by no means in a limiting sense, so as to allow the different features of the invention and the manner of executing the latter to be readily understood.

FIGS. 1 and 2 illustrate in sectional View the rear end of a yielding skirt equipping a platform carried by an air cushion and executed in conformity with the invention, respectively, just before and just after the passage of the rear section of the cushion over a sharp hindrance.

FIG. 3 is a diametrical cross-section of a preferred embodiment applicable chiefly to symmetrical skirts the direction of movement of which is selected as desired.

FIGS. 4 and 5 illustrate on a larger scale in cross-sectional view two detail modifications of the lower edge of a skirt.

The yielding skirts associated with platforms 1 resting on air cushions, chiefly skirts having a circular outline When viewed from above as described by applicant in the above-mentioned specification, show at the rear a curvature and possibly a slope which makes the passage of the platform off a hindrance more difficult than the engagement of the latter under the platform and skirt.

Now, according to the present invention (FIGS. 1 and 2), the deformable skirt having an uninterrupted outline and which is of any suitable shape or material and is secured underneath a platform 1 so as to enclose an air cushion fed with compressed gas through the channel 1a is associated with a gas-permeable partition 3 forming at the rear or output end of the skirt an acute angle A with a horizontal plane, which may be very small. The rear section of said permeable partition is secured to the inside of the lower rear edge 2a of the skirt 2. The front section of said partition is secured either to the actual platform structure at 1c or to the inner surface of the yielding skirt.

Said partition 3 is advantageously made of a yielding meshed material such as Woven or knitted material or again such as a metal gauze. It opposes no substantial resistance to the passage of the compressed gases or air and it does not modify the aerodynamic operation of the skirt. In contra-distinction and as clearly apparent from examination of FIGS. 1 and 2, a hindrance 10 which is about to release the skirt 2 as the latter progresses meets first the partition 3 which is thus tensioned and constrains the skirt to rise whereby the passage of said skirt over the hindrance is furthered.

In the case of symmetrical skirts, chiefly circular skirts adapted to move in all directions, the channel feeding compressed gas 111 (FIG. 3) which may be divergent extends prefer-ably in an axial direction and opens into a distributing chamber 4 closed by a perforated metal sheet 5, The permeable partition 3 secured to the lower edge 2a of the skirt 2 is conical in the present case and its apical angle B may be large .and approximate even The apex of the cone formed by the wall 3 is connected with the stationary structure of the platform by a cable 7 and possibly also by a spring 6 or the like. The angle B which approximates 180 which ensures a practically flat shape for the permeable partition may serve in particular in the case of slowly moving platforms operating as jacks and are used for instance for the shifting of very heavy loads over the floor of a workshop which is generally smooth, but may show locally projections such as anchoring bolts plugged in the ground for temporary adjustments.

The securing of the permeable partition 3 to the lower edge 2a of the skirt 2 may be executed (FIGS. 4 and 5) by means of wires 9, rivets 9a, bolts or even slide fasteners such as those sold under the registered trade name Lightning fasteners. Said securing may also be obtained by fitting a wear-resisting strip 8-8:: which may be made of a cheap, possibly reinforced material resisting abrasion under excellent conditions such as certain plastic materials, chiefly polyvinyl chloride.

Obviously, the invention is not limited to the embodiments specifically described hereinabove and it covers all the modifications falling within the scope of the accompanying claims and which may resort to the use of any equivalent technical means.

What I claim is:

1. In a plenum chamber type ground-effect machine designed to move along rough ground having protruding obstacles, comprising a support frame, a skirt made of supple fluidtight material tensionable by internal overpressure and having a wide-open free end, said skirt depending from said support frame with said free end remote therefrom, so that said skirt defines the lateral boundary of the plenum chamber of the ground efi'ect machine, means on said support frame for delivering pressurized fluid inside said skirt thereby tensioning the same, the improvement having means for detecting an obstacle projecting through said free end into said plenum chamber comprising a sheet-like structure extending inside said skirt across a portion of said plenum chamber and having a widely exposed undersurface to be engaged by such obstacle and upwardly deflected thereby, said sheet-like structure being fluid permeable to an extent as to interpose no substantial resistance to the passage of a fluid therethrough and thereby enabling no modified functioning of the aerodynamic operation of said skirt despite said sheet-like structure being positioned in the plenum chamber and interposed in the flow path, said sheet-like structure being mechanically connected with at least a portion of the free end of said skirt so that said skirt is raised when said sheet-like structure engages an obstacle protruding into said skirt through said free end.

2. Machine as claimed in claim 1, wherein said sheetlike structure is further mechanically connected with said support frame at a point of said sheet-like structure spaced from the connection thereof with said skirt.

3. A machine as claimed in claim 2, comprising spring means in the connection of said sheet-like structure with said support frame.

4. Machine as claimed in claim 1, wherein said sheetlike structure comprises a sheet of meshed material.

5. Machine as claimed in claim 1, wherein said sheetlike structure comprises a sheet of woven material.

6. Machine as claimed in claim 1, wherein said sheetlike structure comprises a sheet of knitted material.

7. Machine as claimed in claim 1, wherein said sheetlike structure comprises a sheet of metal gauze.

8. Machine as claimed in claim 2., wherein said skirt when tensioned has a generally circular cross-section, and wherein said sheet-like structure has a generally conical shape, the base of which is connected with said skirt and the apex of which is connected with said support frame.

9. Machine as claimed in claim 8, comprising a cable in the connection between said apex and said support frame.

References Cited by the Examiner UNITED STATES PATENTS 3,134,452 5/1964 Latimer-Needham l7 3,139,947 7/1964 Beardsley 7 3,168,928 2/1965 Ljungstrom 180-7 BENJAMIN HERSH, Primary Examiner.

A. HARRY LEVY, Examiner.

M. S. SALES, Assistant Examiner. 

1. IN A PLENUM CHAMBER TYPE GROUND-EFFECT MACHINE DESIGNED TO MOVE ALONG ROUGH GROUP HAVING PROTRUDING OBSTACLES, COMPRISING A SUPPORT FRAME, A SKIRT MADE OF SUPPLE FLUIDTIGHT MATERIAL TENSIONABLE BY INTERNAL OVERPRESSURE AND HAVING A WIDE-OPEN FREE END, SAID SKIRT DEPENDING FROM SAID SUPPORT FRAME WITH SAID FREE END REMOTE THEREFROM, SO THAT SAID SKIRT DEFINES THE LATERAL BOUNDARY OF THE PLENUM CHAMBER OF THE GROUND EFFECT MACHINE, MEANS ON SAID SUPPORT FRAME, FOR DELIVERING PRESSURIZED FLUID INSIDE SAID SKIRT THEREBY TENSIONING THE SAME, THE IMPROVEMENT HAVING MEANS FOR DETECTING AN OBSTACLE PROJECTING THROUGH SAID FREE END INTO SAID PLENUM CHAMBER COMPRISING A SHEET-LIKE STRUCTURE EXTENDING INSIDE SAID SKIRT ACROSS A PORTION OF SAID PLENUM CHAMBER AND HAVING A WIDELY EXPOSED UNDERSURFACE TO BE ENGAGED BY SUCH OBSTACLE AND UPWARDLY DEFLECTED THEREBY, SAID SHEET-LIKE STRUCTURE BEING FLUID PERMEABLE TO AN EXTENT AS TO INTERPOSE NO SUBSTANTIAL RESISTANCE TO THE PASSAGE OF A FLUID THERETHROUGH AND THEREBY ENABLING NO MODIFIED FUNCTIONING OF THE AERODYNAMIC OPERATION OF SAID SKIRT DESPITE SAID SHEET-LIKE STRUCTURE BEING POSITIONED IN THE PLENUM CHAMBER AND INTERPOSED IN THE FLOW PATH, SAID SHEET-LIKE STRUCTURE BEING MECHANICALLY CONNECTED WITH AT LEAST A PORTION OF THE FREE END OF SAID SKIRT SO THAT SAID SKIRT IS RAISED WHEN SAID SHEET-LIKE STRUCTURE ENGAGES AN OBSTACLE PROTRUDING INTO SAID SKIRT THROUGH SAID FREE END. 